Hi Stefan, > > > > This is a errta for DCU, Gamma registers are supposed to be big > > endian, but actually it is little endian, do we > > Really need to create a second regmap? > > Do you have the exact wording of the errata? Below is the description from hardware team. Affects: 2D-ACE Description: Gamma_R, Gamma_G and Gamma_B registers are little-endian registers while the rest of the address-space in 2D-ACE is big-endian. 2D-ACE Gamma_R, Gamma_G and Gamma_B registers are 32 bit registers, where the first 24 bits are reserved and last 8 bits denote the gamma value. Because of a connection issue in the device, the first 8-bit [31:24] is connected and the rest of the 24-bits[23:0] are reserved. Impact: Gamma registers are not configurable. Workaround: Perform the byte_swapping for Gamma_[R/G/B]_registers. For example: While writing 0000_00ABh to any of the gamma registers, byte swap the data so it results in AB00_0000h. Write this value to the gamma register. > > There are two problems to the current approach: First, the two byte > swaps (yours and then the byte swap due to the big-endian configuration > of regmap) seems ugly to me. Second, the gamma value is the lowest byte > in Vybrid, and on Vybrid the regmap is configured little-endian. Hence > your code won't work on Vybrid... Therefor I still think that using a > second regmap would be nicer. > Oh sorry, I ignored there are two platforms. Using regmap according to DTS is nicer. Best Regards, Meng _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
